Alvarez had been irked by comments from Mayweather's camp that they had put one over on Canelo by forcing him to weigh in two pounds lower than the usual 154-pound junior-middleweight limit.

During the ceremonies Friday, Alvarez refused to go along with any gamesmanship by the calculating Mayweather, who weighed 150 1/2 pounds in front of a massive, pro-Canelo crowd of 12,200 inside the hotel's Grand Garden Arena.

When someone held up a seven-pound gold World Boxing Council junior-middleweight belt in front of the two fighters, Mayweather pulled the belt away and handed it to a member of his entourage.

Then, Mayweather moved to hold the belt in front of both of them, tightly grabbing Alvarez by the right arm so the Mexican fighter could hold his end of the belt in a pose for photographers.

But Alvarez (42-0-1, 30 knockouts) pulled his arm away, shot Mayweather a dirty look and refused to show any spirit of cooperation with their fight less than 30 hours away.

Later, Alvarez laughed as friends showed him photos of the scene with Mayweather and the belt.

Fight promoter Richard Schaefer said Alvarez told him, "I'm not going to do what that guy tells me. Who the hell does he think he is?"

Mayweather looked surprised by the notion that the youngster was not following the veteran's plan to dictate the scene.

"You know how these kids are," Mayweather said on stage.

Was this development a precursor to the fight Saturday — an indicator that Mayweather will no longer have his way against the younger, stronger and bigger WBC and World Boxing Assn. junior-middleweight champion?

This intrigue is why a record live-gate crowd that spent $20.03 million on tickets will fill the arena Saturday night, and why Mayweather's record $137-million pay-per-view sales for his 2007 fight against Oscar De La Hoya could be broken.

"This turnout was truly amazing," said Mayweather, who'll earn a guaranteed $41.5 million for the bout to Alvarez's guaranteed $5 million, with both boxers getting undisclosed percentages of pay-per-view money. "We're looking to break records, what else can I say?"

After 10 people were shot — seven of them in one incident — overnight in Baltimore following the city's most violent month in decades, police announced Sunday that 10 federal agents will embed with the city's homicide unit for the next two months.